The correct answer is: d) New Alluvial
New Alluvial soil is the most common type of soil in Assam. It is a type of soil that is formed from the deposition of sediments by rivers and streams. New Alluvial soil is typically very fertile and is well-suited for agriculture.
Laterite soil is a type of soil that is formed from the weathering of rocks in tropical climates. Laterite soil is typically very poor in nutrients and is not well-suited for agriculture.
Old Alluvial soil is a type of soil that is formed from the deposition of sediments by rivers and streams over a long period of time. Old Alluvial soil is typically less fertile than New Alluvial soil, but it is still well-suited for agriculture.
Black Soil is a type of soil that is formed from the weathering of volcanic rocks. Black Soil is typically very fertile and is well-suited for agriculture. However, it is not found in Assam.